Dressed in a dark suit and looking pale-faced, Facebook chief Mark Zuckerberg was clearly expecting a tough grilling before the Senate committee. In fact he was largely let off the hook, facing a series of questions that mainly served to expose politicians’ lack of understanding of the social network’s technology. Zuckerberg began by apologizing for his company’s failure to protect users’ data. He admitted Facebook had made “a lot of mistakes” and that it “didn’t do enough” to protect data privacy. However, a series of questions that exposed senators’ lack of understanding of how Facebook works did little to put…